Method of conducting chemical gas experiments and laboratory apparatus for generating gas



Feb. 27, 1968 G. E. TRUEBLOOD METHOD OF CONDUCTING CHEMICAL GASEXPERIMENTS AND LABORATORY APPARATUS FOR GENERATING GAS Filed Feb. 9,1965 INVENTOR. 'era/d 5 7/ aeb/00a I A:TTORNEYS United States Patent3,370,925 METHOD OF CONDUCTING CHEMICAL GAS EX PERIMENTS AND LABORATORYAPPARATUS FOR GENERATING GAS Gerald E. Trueblood, 410 Grant St., Geneva,Ill. 60134 Filed Feb. 9, 1965, Ser. No. 431,408 8 Claims. (Cl. 23211)This invention relates generally to a method of and apparatus forconducting chemical gas experiments in a laboratory and moreparticularly relates to a laboratory method and apparatus for reacting aliquid such as an acid with a specimen such as a metal sample forgenerating a determinable quantum of gas wherein the metal sample iscapsulated within a specimen holder retained in the mouth of agas-generating tube so that all of the reaction liquid is diffusedthrough the specimen holder as gas is generated and trapped within thetube.

An experiment that has long been performed by chemistry students at thehigh school and college levels involves putting a small amount ofconcentrated acid in a gas-measuring tube and then filling the tube tothe mouth thereof with water. A piece of metal is held at the mouth andwhen the tube is inverted in a beaker containing water, the aciddiffuses downwardly until it finally reacts with the metal at the mouthto release a gas which is collected for measurement in the gas-measuringtube. by following such procedures with equipment heretofore provided, aproblem is presented in keeping the metal at the mouth of thegas-measuring tube in order to react properly with the downwarddiffusing acid.

In accordance with the principles of the present invention, a smallflexible plastic capsule adapted to capsulate a metal specimen isinserted into the mouth of a gasmeasuring tube, and the specimen-holdingcapsule is characterized by apertures formed in the walls thereof topermit the acid to enter the capsule and to allow the gas generated toleave the capsule. The capsule is retained in press-fit assembly in themouth of the tube by means of flexible ribs and a plug may be providedwhich not only insures diffusion of the acid through the capsule, butalso facilitates assembly of the specimen holder in the gasmeasuringtube.

It is an object of the present invention, therefore, to provide animproved method of conducting chemical gas experiments in a laboratorywith the use of apparatus overcoming the deficiencies of the prior art.

Another object of the present invention is to provide laboratoryapparatus for generating gas by the reaction of a metal and an acidwherein the metal specimen may be encapsulated in the mouth of agas-generating tube.

Yet another object of the present invention is to provide an improvedspecimen holder adapted to be inserted in the mouth of a gas-measuringtube and which is particularly characterized by means formed thereinpermitting a reaction liquid to diffuse outwardly from the tube throughthe specimen holder and for gas generated by the reaction to be capturedin the tube.

Many other features, additional advantages and further objects of thepresent invention will become manifest to those versed in the art uponmaking reference to the detailed description which follows and theaccompanying sheet of drawings in which a preferred structuralembodiment of my invention is shown by way of illustrative example andby means of which the novel methods contemplated by the presentinvention may be effectively practiced.

As shown on the drawings:

FIGURE 1 is an elevational view of a gas-measuring tube in which thespecimen holder is assembled in the open mouth thereof;

FIGURE 2 is a somewhat schematic view illustrating the gas-measuringtube of FIGURE 1 inverted and with the end thereof in a beaker of water;

FIGURE 3 is a cross-sectional view taken generally on line III-III ofFIGURE 2;

FIGURE 4 is a cross-sectional view taken generally on line IVIV ofFIGURE 3; and

FIGURE 5 is an exploded view showing additional details of constructionof the specimen holder provided in accordance with the principles of thepresent invention for use in a gas-measuring tube.

As shown on the drawings:

A gas-measuring tube is shown generally at 10 and comprises a generallycylindrical tube having a body 11 formed with a calibrated scale 12extending longitudinally along the length thereof from a closed end.13.

Theopposite end of the tube 10 is formed with an opening forming a mouth14. In accordance with operating procedures, the tube 10 may be chargedwith a suitable amount of concentrated acid whereupon the tube is filledto the mouth 14 with water. A metal specimen is then placed at the mouth14 of the tube 10 and the tube is inverted in a beaker containing waterso that the downwardly diifusing acid will react with the metal torelease a gas collected for measurement in the tube 10.

A. beaker is shown at 16 filled with water to a water level shown at 17establishing the organization in which the present invention findsparticular utility.

It is contemplated by the present invention to provide a specimen holderwhich more particularly comprises a capsule shown generally at 20 and aplug shown generally at 21.

More specifically, the capsule constitutes a generally cylindrical tubehaving side walls 22 surrounding an inner bore 23 and having an outerperipheral surface 24.

A plurality of longitudinally extending ribs 26 are formed on theoutside surface of the walls 24 and are spaced circumferentially fromone another. In the preferred embodiment herein illustrated, there arefour ribs 26 spaced from one another in equiangular relationship. Theouter diameter of the walls, measured at the outer surface 24, is lessthan the inner diameter of a standard gas-measuring tube 10. In thisconnection, it is contemplated that the capsule 20 could be made in atleast two different sizes for association with either a 25 milliliter or50 milliliter gas-measuring tube. The outer diameter of the capsule 20measured across the outwardly projecting ribs 26 would be approximatelyequal to the inside diameter of the tube 10.

Each of the ribs or radially outwardly extending projections 26 extendsa substantial distance along the length of the walls 24 in theembodiment herein illustrated, through it will be appreciated that otherphysical forms of ribs or projections could be employed within thespirit and intent of the present invention. In the present embodiment,each rib extends from an end portion 27 at the innermost end of thecapsule 20 and terminates in a cir-,

cumferentially continuous collar 28 formed at the end of capsule 20. Thecollar 28 is of the same outer diameter as the ribs or projections 26and is adapted to be received It will be noted that when the capsule 20is inserted into the mouth 14 of the tube 10, an annular space 32(FIGURE 4) will be left between the outer surface 24 of the capsule 20and the adjoining inner walls of the tube 10. Accordingly, when the tubeis inverted, the liquid contents thereof will freely pass through theapertures 31 into the hollow interior of the capsule 20 provided by thebore 23.

Inwardly of the collar 28, the capsule is characterized by an internallythreaded portion 33 which threadedly receives the externally threadedportion 34 of the plug 21. The plug 21 has a generally cylindrical body36 and a radial end wall 37 from which projects axially a knob 38.

The knob 38 has a neck 39 which joins the main body portion 36 of theplug 21 at a central portion of the end wall 37. At spaced pointsoutwardly of the neck 39, the body 36 of the plug 21 is provided withaxially extending difiusion passages 40 which intersect the end wall 37as well as an end wall 41 at the other end of the body 36.

Both the capsule 20 and the plug 21 are preferably made of a flexible,chemically inert plastic material such as polyethylene. By making theparts of such material, it will be understood that the ribs orprojections 26 will be somewhat elastic as will the collar 28. Moreover,the threaded connection between the threads 33 and 34 can also beconveniently effected.

The tapered nose or conically shaped end portion provided by the Walls29 on the capsule 20 provide a finder portion for piloting the capsuleinto the mouth 14 of the tube 10. In practice, therefore, the tube 10can either be precharged with the requisite amount of reaction liquidsuch as concentrated acid, and a specimen of metal which is shown inFIGURE 3 at S is inserted through the threaded opening 33 into the bore23 of the capsule 20, whereupon the capsule is inserted into the tube 10through the mouth 14. The ribs or projections 26 will slidingly engagethe adjoining inside walls of the tube 10 and the circumferentiallycontinuous surface of the collar 28 will seal the adjoining edges of themouth '14. Either before or after insertion into the tube, the plug 21may be threaded into the end of the capsule 20. By inserting the plug 21into the capsule before insertion, the knob 38 may be advantageouslyused in manipulating the specimen holder and in effecting the insertionthereof into thetube 10.

So inserted, the specimen holder functions to position the metalspecimen S directly in the mouth of the tube 10 so that upon inversionof the tube into a beaker of water, the acid will flow down intosurrounding relationship to the walls 22 and 29 of the capsule and willenter the interior of the capsule into the bore 23 via the apertures 31.Upon reaction with the metal specimen S, gas generated by the reactionwill be released through the apertures 31 into the gas-measuring tube 10and upon displacement of the liquid reaction fluid, the liquid willdififuse outwardly through the diffusion passages 40' in the plug 21 andinto the beaker 16.

There is thus provided 'an improved method and means for generating gasunder safe laboratory conditions. Hazards are eliminated and accuracy inconducting the experiment is insured. Moreover, the specimen holder ofthe present invention can be economically fabricated from suitablechemically inert materials and the device is simple to use and reliablein practice.

Although various minor modifications might be suggested by those versedin the art, it should be understood that I wish to embody within thescope of the patent warranted hereon all such modifications asreasonably and properly come within the scope of my contribution to theart.

I claim as my invention:

1. The method of conducting chemical gas experiments in the laboratorywhich includes the steps of charging a supply of acid into' agas-measuring tube through the mouth of the tube,

confining a piece of metal in a foraminous specimen holder sizedcomplementally to the mouth of the tube,

inserting the specimen holder into the mouth of the tube in press-fitrelationship therewith to retain the specimen in sealed assembly withthe tube at the mouth thereof,

inverting the tube with the mouth of the tube into a beaker of water,

and diffusing the acidthrough the specimen holder in reactive relationwith the metal to release gas for measurement in the inverted tube.

2'. Apparatus for conducting chemical gas-generating experiments in thelaboratory comprising,

a gas-measuring tube having an elongated body portion and an open mouthat one end,

said body portion having a calibrated scale formed thereon for measuringthe contents thereof,

and a specimen holder sized to be press-fit in said mouth,

said specimen holder having walls forming a compartment for holding apiece of metal,

the walls of said specimen holder having diffusion passages forrnedtherethrough, whereby a quantity of acid contained in said tube may bediffused through said passages in reactive relation to metal in saidspecimen holder when the tube is inverted in a breaker of water.

3. In a laboratory apparatus for generating gas by the reaction ofmetaland acid, the improvement of a capsule made of chemically inert flexibleplastic material for insertion into the end of a gas-measuring tubecharged with a reactive liquid, said capsule comprising a generallycylindrical body having cylindrical walls,

aplurality of longitudinally extending radially outwardly projectingribs circumferentially spaced from one another on the peripheral surfaceof said cylindrical walls,

the outer diameter of said body portion walls being less than the innerdiameter of a gasmeasuring tube and the outer diametral dimensionmeasured across said ribs being substantially equal to the innerdiameter of the gas-measuring tube,

said ribsbeing sufliciently elastic to adapt said capsule for a slidingpress-fit into the mouth of a gas-measuring tube with said walls spacedfrom the adjoining tube walls,

said body terminating at one end in a convergent longitudinallyextending end wall closing one end of the body,

' the other end of said body having an internally threaded mouth openingformed therein through which a specimen adapted to react with saidliquid may be inserted for containment in said capsule,

and a plug made of flexible chemically inert plastic material having anexternally threaded neck portion threaded into said mouth opening,

said body having a circumferentially continuous end collar for overlyingsaid ribs and sealing in press-fit relationship against the adjoiningwalls of the gas-measuring tube to close thespace between the walls ofthe gas-measuring tube and the'capsule, said plug having axiallyextending diflfusion passages formed therein for diffusing the liquidcontents of said capsule outwardly when the gas-measuring tube isinverted in a beaker of water, a said walls of said capsule being formedwith openings to direct the reaction liquid from the interior of thegas-measuring tube when inverted through the capsule for reaction withthe speci men,

said plug having an axially outwardly projecting knob for manipulatingthe plug.

4. Laboratory apparatus for reactmg liquid .acid with a metal specimenin generating a determinable quantum of gas, comprising,

a generally tubular laboratory tube closed at one end, open at the otherend and formed with a calibrated scale between the opposite ends andadapted to be charged with a quantity of liquid acid when positioneduprightly,

a specimen holder inserted in said tube at its open end comprising acapsule having outwardly extending projections engaging the adjoiningside walls of the tube, thereby leaving a space around the capsule,

said capsule having :a compartment formed therein and being open at oneend to receive a metal specimen in said compartment,

the walls of said capsule being apertured to form diffusion passagestherein communicating the interior of the capsule with the interior ofthe tube, and a plug threaded into the open end of said capsule andhaving axially extending diffusion passages formed therein so that whenthe tube is inverted and the open end thereof placed in a beaker ofwater the acid in the tube will pass through the diffusion passages inthe capsule walls for reaction with the metal specimen and will bedisplaced through the diffusion passages in the plug when gas isgenerated and trapped in the inverted tube.

5. Laboratory apparatus as defined in claim 4 and further characterizedby said specimen holder having circumferentially continuous sealingmeans engaging the walls of the tube to insure that .all of the acid inthe tube will be directed through the capsule for reaction with thespecimen.

6. Laboratory apparatus as defined in claim 5 and further characterizedby said specimen holder being made of flexible chemically inert plasticmaterial so that said ribs and said plug Will be sufiiciently elastic topromote press-fit sealing relationships with adjoining parts.

7. Laboratory apparatus as defined in claim 6 and further characterizedby said capsule including a tapered convergent end wall forming a finderportion for piloting the capsule into the end of the tube.

8. Laboratory apparatus as defined in claim 7 and further characterizedby said plug having a knob extending outwardly in an axial direction formanipulation dur ing insertion and extraction from the tube and thecapsule.

References Cited UNITED STATES PATENTS 1,507,060 9/1924 Hayes 23-2821,518,999 12/ 1924 Miller 23-272.8

FOREIGN PATENTS 954,642 4/ 1964 Great Britain.

MORRIS O. WOLK, Primary Examiner. JAMES H. TAYMAN, JR., Examiner.

1. THE METHOD OF CONDUCTING CHEMICAL GAS EXPERIMENTS IN THE LABORATORYWHICH INCLUDES THE STEPS OF CHARGING A SUPPLY OF ACID INTO AGAS-MEASURING TUBE THROUGH THE MOUGH OF THE TUBE, CONFINING A PIECE OFMETAL IN A FORAMINOUS SPECIMEN HOLDER SIEZED COMPLEMENTALLY TO THE MOUTHOF THE TUBE, INSERTING THE SPECIMEN HOLDER INTO THE MOUTH OF THE TUBE INPRESS-FIT RELATIONSHIP THEREWITH TO RETAIN THE SPECIMEN IN SEALEDASSEMBLY WITH THE TUBE AT THE MOUTH THEREOF, INVERTING THE TUBE WITH THEMOUTH OF THE TUBE INTO A BEAKER OF WATER, AND DIFFUSING THE ACID THROUGHTHE SPECIMEN HOLDER IN REACTIVE RELATION WITH THE METAL TO RELEASE GASFOR MEASUREMENT IN THE INVERTED TUBE.